The present invention relates broadly to power tools for installing plastic hose or bundle clamps. More specifically, the present invention relates to an ergonomic, pneumatically-powered hand tool for installing resilient tube clamps on hoses, wire bundles, or the like.
As will be appreciated by those experienced in the art, it is extremely important to achieve a leak-proof coupling between hose sections that are to be joined. In the early years of the art, hose clamps commonly comprised a length of wire or other resilient metal adapted to be twisted tightly about the tubes to be connected. Various tools were developed for twisting the ends of the wire tightly together. Representative of such art is Clayton, U.S. Pat. No. 3,800,634, issued Apr. 2, 1974; U.S. Pat. No. 4,368,569 issued Jan. 18, 1983 to Van Dam; and, Lewis, U.S. Pat. No. 4,091,483 issued May 30, 1978. An automated wire clamping tool is taught by Chrisley in U.S. Pat. No. 4,747,432 issued May 31, 1988.
However, in recent years, resilient, plastic hose clamps enjoy increased popularity, and the last-mentioned wire-twist tools are not well-suited for use therewith. The plastic clamps are more resilient, less prone to deterioration from exposure, capable of maintaining a tighter grip, and generally more economical than their metallic forerunners. Representative of the art in modern resilient clamps are the following U.S. patents: Due, U.S. Pat. No. 4,935,992; Vallinotto, U.S. Pat. No. 3,605,200; Wenk, U.S. Pat. No. 4,128,918; and Bevins, U.S. Pat. No. 3,925,851. Such clamps broadly comprise a resilient, circular band and an integral head having a pair of interlocking jaws. A plurality of teeth associated with the jaws lock together to achieve a secure coupling. In order to achieve proper locking, the jaws must be maintained in proper alignment and retained against lateral or torsional displacement during installation.
Unfortunately, proper alignment and locking are difficult to achieve by manual installation. Thomas U.S. Pat. No. 3,266,109 issued Aug. 16, 1966 illustrates the use of ordinary pliers for installing a locking clamp about a hose. However, based on our experimentation, manual force applied via such conventional plier tools is inadequate for achieving a satisfactory lock.
Hand-held pliers generally cannot deliver adequate locking power. Importantly, pliers do not provide means for firmly retaining the clamp against lateral or torsional displacement during installation.
Hence, various power tools have been proposed in the art. The pneumatic clamp-tightening tool of Dixon, U.S. Pat. No. 4,747,433, issued May 31, 1988 comprises a hand-held pneumatic gun actuating a slidable ram, which in turn rotates a pivotal head. The head grasps a free end of a flexible wire tie and pulls it tightly about the periphery of the hose. A serrated nose frictionally engages the locking head of the tie during tightening.
A similar concept is advanced in U.S. Pat. No. 3,661,187 issued May 9, 1972 to Caveney. Therein is disclosed a hand-held, pneumatically actuated strap puller. The puller pivots in response to actuation of an interiorly disposed ram. As it pivots, the head draws the free end of the strap fastener into the machine until the strap is tightly fastened about the wire bundle. Thereafter, the machine severs the remaining loose end of the strap and locks the bound end in place.
The aforedescribed clamp art provides no guidance for the proper, leak-proof installation of locking clamps. There are provided no means for properly grasping and retaining the locking head of a clamp in alignment prior to installation. Moreover, the pulling or twisting pressure applied by such tools is generally not adequate for pressing the cooperating jaw members of various types of clamps into locking engagement. Depending upon the size and bulk of the hose or bundle to be clamped, we have found it desirable to deliver clamping pressures between twenty and 150 psi.
One very relevant prior art tool is disclosed by Pawloski, in U.S. Pat. No. 3,269,223 issued Aug. 30, 1966. The tool comprises an elongated body terminating at one end in a clamping jaw and its opposite end in a valve assembly adapted to be coupled to an external fluid source. Activation of the tool is achieved by compressing a spring-biased button, which drives an interior plunger forward into the gripping head. The plunger forcibly contacts roller heads, which in turn rotate the gripping jaws into an open position. The cooperating jaws are biased to a closed position by a torsion spring. The Powloski tool fails to provide means for securely gripping a resilient locking clamp. There are no means for controlling torsional displacement of the clamp during installation and locking. Moreover the elongated body can be cumbersome and difficult to manipulate, because the body must be held in alignment with the clamp. In addition, the jaws of the tool provide no gripping surface for engaging clamps or locks of various types.
Hence, it is desired to provide a hand-held, power tool capable of maintaining the cooperative jaws of a locking clamp in alignment while delivering selectively variable amounts of locking pressure.